1. Field of the Invention
The present invention relates, in general, to a spray nozzle assembly, and in particular, to a die lubricant spray nozzle assembly which can be used to atomizingly spray a plurality of short bursts of a metered amount of die lubricant without substantial dripping.
2. Information Disclosure Statement
It is often desirable to apply a die lubricant to a die of a die press and/or to the workpiece being processed.
In many prior art air-driven die lubricant systems, the die lubricant is atomized by mixing compressed air with the die lubricant in an atomizing chamber, and the air and lubricant mixture is then directed through a spray tip, on a continuous-feed basis, to the die and/or the workpiece. A large volume of compressed air, having a high velocity, is typically used in the prior art to atomize the die lubricant into fine particles. Because the velocity of the air and die lubricant mixture is so great as it passes through the spray tip and contacts the die, a large volume of the die lubricant typically bounces off of the die and the workpiece. This causes inefficient utilization of the die lubricant, and the accumulation of this reflected die lubricant in the work area causes an environmental and safety hazard. Additionally, a large percentage of dies operate in excess of 500 degrees Fahrenheit (260 degrees Celsius), and it has been experimentally found that when die lubricant contacts a die operating in excess of 500 degrees Fahrenheit (260 degrees Celsius), a steam barrier is generated that acts to repel the die lubricant from the die and the lubricated workpiece. The velocity of the die lubricant must therefore be increased in order to penetrate this steam barrier, and this increased velocity causes a still-greater volume of die lubricant to bounce off of the die and workpiece. The result is an increased inefficiency in the utilization of the die lubricant and an increased environmental and safety hazard in the work area.
Even when airless prior art nozzle assemblies are used to atomize bursts of die lubricant, they do not atomize the die lubricant to the extent desired and produce lubricant drip following each short burst of a metered amount of the die lubricant. Similar to the effect observed with air-driven prior art nozzle assemblies, a steam barrier is generated when the die lubricant contacts a die operating in excess of 500 degrees Fahrenheit (260 degrees Celsius), thereby creating a problem of repulsion of the next short burst of the metered amount of die lubricant.
It is therefore desirable to have a lubricant driven system having an improved die lubricant spray nozzle assembly that can deliver a plurality of short bursts of a precisely metered amount of die lubricant while substantially eliminating the problem of die lubricant drip following each one of the bursts, and that can also provide significant atoniization of the die lubricant as it exits the nozzle assembly. It is also desirable to have a method of using the nozzle assembly which will eliminate the problem of die lubricant repulsion associated with the creation of a steam barrier.
A preliminary patentability search in Class 239 subclasses 533.1, 568, 575, 590, 597, 598, and 599 and in Class 164 subclass 72, produced the following patents, some of which may be relevant to the present invention: Gigantino et al., U.S. Pat. No. 3,510,065, issued May 5, 1970; Heron et al., U.S. Pat. No. 4,878,785, issued Nov. 7, 1989; Bendig et al., U.S. Pat. No. 4,989,788, issued Feb. 5, 1991; and Herstek et al., U.S. Pat. No. 5,288,027, issued Feb. 22, 1994. Gigantino et al. discloses a nozzle having a non-atomizing spray tip that is designed to deliver a continuous spray of water having a high pressure, 1800 to 3000 pounds per square inch, at a high velocity. Heron et al. discloses a nozzle that is designed to continuously deliver an abrasive fluid at a high velocity and to direct the abrasive fluid towards the center of an internal cross-sectional area of the nozzle in order to reduce wear of the internal cross-sectional area, and the nozzle is designed to have an elongated non-atomizing spray tip.
The inventor is also aware of the following related reference that may be relevant to the present invention: Hayes, U.S. Pat. No. 5,531,085, issued Jul. 2, 1996, which describes a die lubricant applicator for delivering precisely metered bursts of die lubricant.
None of these references, either singly or in combination, disclose or suggest the present invention.